MILLIONS of patients are at risk because of widespread confusion over the prescribing of powerful heart pills.

At least one in 10 of those given the cholesterol-busting statins may be taking them unnecessarily, research reveals.

Researchers have also uncovered evidence that less than a third of patients who should be taking statins are being prescribed them.

Experts blame the shocking lapse on con­fusion among family doctors about which “risk assessment” they should be using to determine who needs the drug.

It means people not being given the pills have a dramatically higher chance of suffering a heart attack or stroke. And those taking them when they are not at risk could be suffering debilitating side effects such as muscle pain, kidney damage and dia­betes.

The researchers, from the University of Birmingham, conclude that statin prescribing is “very unfocused” and based too much on specific rather than overall risk factors.

Their work comes amid concerns about over-prescribing of the cheap heart pills.

Many experts have called for everyone over 50 to be given statins, which they estimate could save at least 2,000 lives a year.

Others say the pills, which cost as little as 4p a day and are taken by eight million Britons to reduce cholesterol and protect against heart attacks, heart disease and stroke, should be prescribed with caution because not enough is known about their side-effects.

The latest research, published online in the journal PLoS ONE, found about one in 10 patients prescribed statins in the UK – around 800,000 people – is not at high risk of cardiovascular disease. The findings, from an analysis of medical records at 420 GPs’ surgeries, indicate most patients prescribed statins are not strictly eligible for the treatment based on their “global” risk.

Less than a third of patients who should be takin statins aren't (PIC POSED BY MODELS)

People not being given the pills have a dramatically higher chance of suffering a heart attack or stroke

Lead researcher Dr Tom Marshall told Pulse, the magazine for GPs, that many doctors were prescribing statins according to ­specific risk factors rather than the “global risk score” recommended in guidelines.

He said: “We found that prescribing was strongly influenced by specific risk factors. That is why having diabetes or a high cholesterol level are very strongly linked to prescribing statins. But there are patients with normal cholesterol levels who are high risk – usually because they are older and have other risk factors – and there are patients with high cholesterol who are not high risk. So this is not a good substitute for the risk score.”

Dr Christine A’Court, clinical researcher at the University of Oxford and a GP in Carterton, Oxfordshire, said the findings were “depressing”. But Dr Alan Begg, a GP in Montrose, Angus, said they were not surprising and that GPs “get mixed messages on what score to use and confusion leads to lack of use”.

Amy Thompson, senior cardiac nurse at the British Heart Foundation, said: “Current guidelines recommend looking at multiple risk factors to work out an overall risk score.

“The risk score plays a big role in whether doctors will prescribe statins. This paper suggests there is still room for improvement. However, the data used is a few years old and it is likely current figures paint a different picture.”